Determination of enhanced physical downlink control channel candidates in a wireless communication network

ABSTRACT

In embodiments, an evolved Node B (eNB) of a wireless communication network may configure an enhanced physical downlink control channel (EPDCCH) physical resource block (PRB) set for a user equipment (UE). The EPDCCH-PRB set may include a plurality of PRB-pairs. The EPDCCH-PRB set may further include a plurality of enhanced resource element groups (EREGs) organized into localized enhanced control channel elements (ECCEs) having EREGs of the same PRB-pair and distributed ECCEs having EREGs of different PRB-pairs. In some embodiments, the eNB may determine a set of distributed EPDCCH candidates for the UE from the EPDCCH-PRB set, wherein the individual distributed EPDCCH candidates include one or more of the distributed ECCEs, and wherein the set of distributed EPDCCH candidates includes at least one EREG from each of the plurality of localized ECCEs. Other embodiments may be described and claimed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/743,205, filed Jun. 18, 2015, entitled “DETERMINATION OFENHANCED PHYSICAL DOWNLINK CONTROL CHANNEL CANDIDATES IN A WIRELESSCOMMUNICATION NETWORK,” which is a continuation of U.S. patentapplication Ser. No. 13/830,277, filed Mar. 14, 2013, entitled“DETERMINATION OF ENHANCED PHYSICAL DOWNLINK CONTROL CHANNEL CANDIDATESIN A WIRELESS COMMUNICATION NETWORK,” which claims priority to U.S.Provisional Patent Application No. 61/707,784, filed Sep. 28, 2012,entitled “ADVANCED WIRELESS COMMUNICATION SYSTEMS AND TECHNIQUES”. Theentire disclosures of which are hereby incorporated by reference intheir entireties.

FIELD

Embodiments of the present invention relate generally to the field ofcommunications, and more particularly, to determination of enhancedphysical downlink control channel candidates in a wireless communicationnetwork.

BACKGROUND

In wireless communication networks, an evolved Node B (eNB) transmits acontrol channel, such as an enhanced physical downlink control channel(EPDCCH) to a user equipment (UE). The EPDCCH includes downlink controlinformation (DCI) with information used by the UE to receive a physicaldownlink shared channel (PDSCH). In many wireless communicationnetworks, the eNB may use either localized or distributed transmissionof the ePDCCH.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings. To facilitatethis description, like reference numerals designate like structuralelements. Embodiments are illustrated by way of example and not by wayof limitation in the figures of the accompanying drawings.

FIG. 1 is a block diagram illustrating wireless communication network inaccordance with various embodiments.

FIG. 2 is a block diagram of an enhanced physical downlink controlchannel (EPDCCH) physical resource block (PRB) set in accordance withvarious embodiments.

FIG. 3 is a diagram illustrating a mapping scheme for mapping ofenhanced resource element groups (eREGs) of the PRB pairs of theEPDCCH-PRB set of FIG. 2 to respective distributed enhanced controlchannel elements (ECCEs), in accordance with various embodiments.

FIG. 4 is a diagram illustrating an EPDCCH candidate determinationscheme for determining ECCEs included in EPDCCH candidates of differentaggregation levels, in accordance with various embodiments.

FIG. 5 is a flowchart illustrating a method of configuring a UE specificsearch space that may be performed by an evolved Node B (eNB) inaccordance with various embodiments.

FIG. 6 is a flowchart illustrating a method to facilitate receiving anEPDCCH that may be performed by a user equipment in accordance withvarious embodiments.

FIG. 7 is a block diagram illustrating an example computing system inaccordance with various embodiments.

DETAILED DESCRIPTION

Illustrative embodiments of the present disclosure include, but are notlimited to, methods, systems, and apparatuses for mapping enhancedphysical downlink control channels in a wireless communication network.

Various aspects of the illustrative embodiments will be described usingterms commonly employed by those skilled in the art to convey thesubstance of their work to others skilled in the art. However, it willbe apparent to those skilled in the art that alternate embodiments maybe practiced with only some of the described aspects. For purposes ofexplanation, specific numbers, materials, and configurations are setforth in order to provide a thorough understanding of the illustrativeembodiments. However, it will be apparent to one skilled in the art thatalternate embodiments may be practiced without the specific details. Inother instances, well-known features are omitted or simplified in ordernot to obscure the illustrative embodiments.

Further, various operations will be described as multiple discreteoperations, in turn, in a manner that is most helpful in understandingthe illustrative embodiments; however, the order of description shouldnot be construed as to imply that these operations are necessarily orderdependent. In particular, these operations need not be performed in theorder of presentation.

The phrase “in some embodiments” is used repeatedly. The phrasegenerally does not refer to the same embodiments; however, it may. Theterms “comprising,” “having,” and “including” are synonymous, unless thecontext dictates otherwise. The phrase “A and/or B” means (A), (B), or(A and B). The phrase “A/B” means (A), (B), or (A and B), similar to thephrase “A and/or B”. The phrase “at least one of A, B and C” means (A),(B), (C), (A and B), (A and C), (B and C) or (A, B and C). The phrase“(A) B” means (B) or (A and B), that is, A is optional.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a wide variety of alternate and/or equivalent implementations maybe substituted for the specific embodiments shown and described, withoutdeparting from the scope of the embodiments of the present disclosure.This application is intended to cover any adaptations or variations ofthe embodiments discussed herein. Therefore, it is manifestly intendedthat the embodiments of the present disclosure be limited only by theclaims and the equivalents thereof.

As used herein, the term “module” may refer to, be part of, or includean Application Specific Integrated Circuit (ASIC), an electroniccircuit, a processor (shared, dedicated, or group) and/or memory(shared, dedicated, or group) that execute one or more software orfirmware programs, a combinational logic circuit, and/or other suitablecomponents that provide the described functionality.

FIG. 1 schematically illustrates a wireless communication network 100 inaccordance with various embodiments. Wireless communication network 100(hereinafter “network 100”) may be an access network of a 3rd GenerationPartnership Project (3GPP) long-term evolution (LTE) network such asevolved universal mobile telecommunication system (UMTS) terrestrialradio access network (E-UTRAN). The network 100 may include a basestation, e.g., evolved Node B (eNB) 104, configured to wirelesslycommunicate with a user equipment (UE) 108. The network 100 may furtherinclude one or more additional UEs, e.g., UEs 112 and 116, thatwirelessly communicate with eNB 104.

The UE 108 may include a communications module 120 and a decoding module124 coupled with one another. The communications module 120 maycommunicate (e.g., transmit and/or receive) with the eNB 104 over thenetwork 100. The decoding module 124 may decode control channelsreceived by the communications module 120, as further discussed below.

The communications module 120 may be further coupled to one or moreantennas 128 to facilitate communication over the network 100. The UE108 may include any suitable number of antennas 128. In variousembodiments, the UE 108 may include at least as many antennas 128 as anumber of simultaneous spatial layers or streams received by the UE 108from the eNB 104, although the scope of the present disclosure may notbe limited in this respect.

One or more of the antennas 128 may be alternately used as transmit orreceive antennas. Alternatively, or additionally, one or more of theantennas 128 may be dedicated receive antennas or dedicated transmitantennas.

Though not shown explicitly, the UEs 112 and 116 may includemodules/components similar to those of the UE 104.

eNB 104 may include a communications module 132 and a control module 136coupled with one another. The communications module 132 may be furthercoupled with one or more antennas 140 of the eNB 104. The communicationsmodule 132 may communicate (e.g., transmit and/or receive) with one ormore UEs (e.g., UEs 108, 112, and/or 116) over the network 100. Invarious embodiments, the eNB 104 may include at least as many antennas140 as a number of simultaneous transmission streams transmitted to theUE 108, although the scope of the present disclosure may not be limitedin this respect. One or more of the antennas 140 may be alternately usedas transmit or receive antennas. Alternatively, or additionally, one ormore of the antennas 140 may be dedicated receive antennas or dedicatedtransmit antennas.

In various embodiments, the control module 136 may generate an enhancedphysical downlink control channel (EPDCCH) for transmission to the UE108. The EPDCCH may include downlink control information (DCI) for theUE 108. The DCI may include, for example, information related toscheduling of downlink resources for a physical downlink shared channel(PDSCH), scheduling of uplink resources for a physical uplink sharedchannel (PUSCH), and/or transmit power control commands for the PUSCHand/or a physical uplink control channel (PUCCH).

In various embodiments, the control module 136 may configure, for the UE108, an EPDCCH-physical resource block (EPDCCH-PRB) set including aplurality of physical resource block (PRB) pairs. The plurality ofPRB-pairs may include a plurality of enhanced control channel elements(ECCEs) and the ECCEs may include a plurality of enhanced resourceelement groups (EREGs). The control module 136 may then determine a setof EPDCCH candidates for the UE from the EPDCCH-PRB set. The EPDCCHcandidates may correspond to one or more ECCEs of the EPDCCH-PRB setthat the UE is to monitor for an EPDCCH for the UE 108.

The EREGs of the plurality of PRB-pairs may be organized into localizedECCEs having EREGs of a same PRB-pair and distributed ECCEs having EREGsdistributed among the plurality of PRB-pairs. For example, thedistributed ECCEs may include one or more EREGs from each PRB-pair ofthe EPDCCH-PRB set.

FIG. 2 illustrates an EPDCCH-PRB set 200 in accordance with someembodiments. The EPDCCH-PRB set 200 includes four PRB-pairs (e.g., PRBa,PRBb, PRBc, and PRBd). Other embodiments may include another number ofPRB-pairs. In some embodiments, the PRBs of the EPDCCH-PRB set 200 maybe separated in the frequency domain. For example, the PRBs of theEPDCCH-PRB set 200 may be distributed in a control region of thefrequency spectrum used by the wireless network (e.g., wireless network100).

The individual PRB pairs (e.g., PRBa, PRBb, PRBc, and PRBd) of theEPDCCH-PRB set 200 may include a plurality of EREGs (e.g., 16 EREGsincluding EREG0, EREG1, . . . , EREG15). The EREGs may be organized intolocalized ECCEs having EREGs from the same PRB-pair. In someembodiments, the localized ECCEs may include EREGs of the samefrequency. For example, the individual PRB-pairs may include fourlocalized ECCEs (e.g., LECCE0, LECCE1, LECCE2, and LECCE3). LECCE0 mayinclude EREG0, EREG4, EREG8, and EREG12, which may all have the samefrequency and may be different in the time domain. In variousembodiments, the number, n, of localized ECCEs of the EPDCCH-PRB set maybe indexed from 0 to n−1 (e.g., LECCE0 to LECCE15 for EPDCCH-PRB set200).

In various embodiments, the EREGs of the EPDCCH-PRB set 200 may furtherbe organized into distributed ECCEs having EREGs from differentPRB-pairs. For example, in some embodiments, the EPDCCH-PRB set 200 mayinclude sixteen distributed ECCEs with the individual distributed ECCEsincluding the EREGs of the plurality of PRB-pairs with the same index(e.g., EREG0 of PRBa, PRBb, PRBc, and PRBd). The distributed ECCEs maybe indexed from 0 to n−1 (e.g., DECCE0 to DECCE15 for EPDCCH-PRB set200). In some embodiments, the indexes of the distributed ECCEs mayincrease first within the same set of localized ECCEs before proceedingto the next set of localized ECCEs.

For example, FIG. 3 illustrates an EPDCCH-PRB set 300 showing themapping of EREGs to distributed ECCEs. The EPDCCH-PRB set 300 maycorrespond to the EPDCCH-PRB set 200 of FIG. 2, and may includePRB-pairs PRBa, PRBb, PRBc, and PRBd. The PRB-pairs may include aplurality of localized ECCEs including respective groups of EREGs. Thelocalized ECCEs may include internal indexes within each PRB-pair (e.g.,LECCE0, LECCE1, LECCE2, and LECCE3).

In various embodiments, the individual distributed ECCEs may includeEREGs from a plurality of the PRB-pairs. For example, the distributedECCEs may include one EREG from each of the PRB-pairs of the EPDCCH-PRBset 300. In some embodiments, an individual distributed ECCE may includeEREGs from the same localized ECCE (e.g., ECCE0) of different PRB-pairs.In some embodiments, the EREGs of the same distributed ECCE may includean EREG of a different index from each of the PRB-pairs. For example, asshown in FIG. 3, DECCE0 may include EREG0 from PRBa, EREG4 from PRBb,EREG8 from PRBc and EREG12 from PRBd. Additionally, DECCE1 may includeEREG4 from the PRBa, EREG8 from PRBb, EREG12 from PRBc and EREG0 fromPRBd. DECCE4 may include EREG1 from PRBa, EREG5 from PRBb, EREG9 fromPRBc and EREG13 from PRBd.

In various embodiments, the control module 136 may determine a set ofEPDCCH candidates from the EPDCCH-PRB set. The EPDCCH candidates maycorrespond to one or more ECCEs of the EPDCCH-PRB set. The set of EPDCCHcandidates may be referred to as blind decoding candidates, and maydefine a UE-specific search space of the UE 108. The control module 136may transmit an EPDCCH for the UE 108, via the communications module132, on one of the EPDCCH candidates. The decoding module 124 of the UE108 may monitor the EPDCCH candidates, and may decode EPDCCHs receivedon all of the EPDCCH candidates to find the EPDCCH designated for the UE108. The UE 108 may successfully decode the PDCCH designated for the UE108 by using a UE-specific scrambling code.

In various embodiments, the control module 136 may configure theEPDCCH-PRB set for the UE as either a localized EPDCCH-PRB set used toindicate localized EPDCCH candidates or a distributed EPDCCH-PRB setused to indicate distributed EPDCCH candidates. In some embodiments, thecontrol module 136 may configure a plurality of EPDCCH-PRB sets for theUE 108. The plurality of EPDCCH-PRB sets may be fully overlapping(including all the same PRB-pairs), partially overlapping (includingsome of the same PRB-pairs), or non-overlapping (including all differentPRB-pairs). The plurality of EPDCCH-PRB sets for the UE 108 may be alllocalized, all distributed, or a combination of localized anddistributed EPDCCH-PRB sets.

Additionally, in some embodiments, the control module 136 may configureEPDCCH-PRB sets for other UEs (e.g., UE 112 or UE 116) that may includeone or more of the same PRB-pairs as the EPDCCH-PRB set for the UE 108.In some embodiments, the plurality of EPDCCH-PRB sets including the samePRB-pairs may be a combination of localized and distributed EPDCCH-PRBsets.

In various embodiments, the EPDCCH candidates may have an aggregationlevel that corresponds to a number of ECCEs in the EPDCCH candidate(e.g., the number of ECCEs used to send the EPDCCH over the EPDCCHcandidate). For example, the aggregation level may be 1, 2, 4, 8, oranother suitable value. The control module 136 may transmit the EPDCCHfor the UE 108 on all of the ECCEs in the EPDCCH candidate selected forEPDCCH transmission. For a localized EPDCCH candidate of aggregationlevel 2 or greater, the localized EPDCCH candidate may first includelocalized ECCEs of the same PRB-pair until no more localized ECCEs ofthe same PRB-pair are available, and then may include localized ECCEs ofanother PRB-pair. For a distributed EPDCCH candidate of aggregationlevel 2 or greater, the distributed EPDCCH may first include distributedECCEs from the same set of localized ECCEs until no more distributedECCEs from the same set of localized ECCEs are available, and may theninclude distributed ECCEs from a different set of localized ECCEs.

In various embodiments, the set of EPDCCH candidates determined by thecontrol module 136 may include any suitable number of EPDCCH candidates.In some embodiments, the number of EPDCCH candidates determined by thecontrol module 136 for the UE 108 may depend on the aggregation level ofthe EPDCCH candidates and/or other factors. For example, as furtherdiscussed below, in embodiments in which a plurality of EPDCCH-PRB setsare configured for the same UE (e.g., UE 108), the number of EPDCCHcandidates determined for the individual EPDCCH-PRB sets may beproportional to the number of PRB-pairs in the respective individualEPDCCH-PRB sets.

In various embodiments, for a localized EPDCCH-PRB set, the controlmodule 136 may spread the localized EPDCCH candidates among theplurality of PRB-pairs of the EPDCCH-PRB set. The different localizedEPDCCH candidates may first include ECCEs of different PRB-pairs (e.g.,until the set of EPDCCH candidates includes an ECCE in each of thePRB-pairs) and then include ECCEs of a same PRB-pair. For example, ifthe set of localized EPDCCH candidates include a number of localizedEPDCCH candidates that is equal to or more than the number of PRB-pairsin the EPDCCH-PRB set, the localized EPDCCH candidates may include atleast one localized ECCE from each of the plurality of PRB-pairs of theEPDCCH-PRB set. If the number of localized EPDCCH candidates in theEPDCCH-PRB set is less than the number of PRB-pairs, the localizedEPDCCH candidates may include localized ECCEs from different PRB-pairs.

The spreading of the localized EPDCCH candidates over the PRB-pairs mayprovide localized EPDCCH candidates over a wide range of frequencies toallow the eNB 104 to take advantage of frequency domain scheduling gain.For example, the UE 108 may provide the eNB 104 with feedbackinformation (e.g., channel state information (CSI)) associated with thePRB-pairs of the EPDCCH-PRB set. The eNB 108 may use the feedbackinformation to determine which EPDCCH candidate to select for sendingthe EPDCCH for the UE 108.

Prior techniques for determining EPDCCH candidates would select a set ofEPDCCH candidates with continuous indexes (e.g., a set of six EPDCCHcandidates including ECCE8 to ECCE13). Referring to the EPDCCH-PRB set200, such a set of EPDCCH candidates would leave two PRB-pairs (e.g.,PRBa and PRBb) without an EPDCCH candidate, which would not give the eNB104 the option of using the frequencies of those PRB-pairs for sendingthe EPDCCH for the UE 108.

Additionally, or alternatively, in various embodiments, for distributedEPDCCH-PRB set, the control module 136 may spread the distributed EPDCCHcandidates among the localized ECCEs of the EPDCCH-PRB set. Thedifferent distributed EPDCCH candidates of the set of distributed EPDCCHcandidates may first be mapped to distributed ECCEs including EREGs ofdifferent localized ECCEs of the PRB-pairs (e.g., until the set ofdistributed EPDCCH candidates includes at least one EREG of eachlocalized ECCE), and may then be mapped to distributed ECCEs includingEREGs of a same localized ECCE as another distributed EPDCCH candidate.

For example, if the number of distributed EPDCCH candidates in the setof distributed EPDCCH candidates is equal to or greater than the numberof PRB-pairs in the EPDCCH-PRB set, the set of distributed EPDCCHcandidates may include at least one EREG from each of the plurality oflocalized ECCEs of the EPDCCH-PRB set. If the number of distributedEPDCCH candidates in the EPDCCH-PRB set is less than the number ofPRB-pairs, the distributed EPDCCH candidates may include distributedECCEs associated with EREGs from different localized ECCEs.

The spreading of the distributed EPDCCH candidates over the localizedECCEs may facilitate efficient use of the REGs of the PRB-pairs, inparticular in situations in which localized and distributed EPDCCH-PRBsets may be configured for the same PRB-pairs. For example, thespreading of the distributed EPDCCH candidates may reduce blocking oflocalized EPDCCH candidates by distributed EPDCCH candidates comparedwith using a set of distributed EPDCCH candidates corresponding todistributed ECCEs with consecutive indexes.

FIG. 4 illustrates a table 400 showing an example set of EPDCCHcandidates for aggregation levels 1, 2, 4, and 8 in one localized EPDCCHset and/or one distributed EPDCCH set, in accordance with someembodiments. The sets of EPDCCH candidates for aggregation levels 1 and2 may include six EPDCCH candidates, while the sets of EPDCCH candidatesfor aggregation levels 4 and 8 may include two EPDCCH candidates. Otherembodiments may include other suitable numbers of EPDCCH candidates forthe respective aggregation levels.

In various embodiments, the ECCE indexes shown in table 400 maycorrespond to the localized ECCEs shown in FIG. 2 or the distributedECCEs shown in FIG. 3. In some embodiments, the table 400 may be usedfor both localized ECCEs and distributed ECCEs. With reference to FIGS.2 and 3, the table 400 may provide localized EPDCCH candidates spreadamong the PRB-pairs of the EPDCCH-PRB set, and may provide distributedEPDCCH candidates spread among the localized ECCEs of the EPDCCH-PRBset.

For example, for localized EPDCCH candidates of aggregation level 1, theEPDCCH candidates with indexes 0 to 3 may be spread over the four PRBpairs of the EPDCCH-PRB set 200. The EPDCCH candidates with indexes 4and 5 may be further spread over the frequency spectrum by placing themin PRBa and PRBc. For distributed EPDCCH candidates of aggregation level1, the distributed EPDCCH candidates with indexes 0 to 3 maycollectively include EREGs from all of the localized ECCEs of EPDCCH-PRBset 200.

In some embodiments, the control module 136 may determine the localizedand/or distributed EPDCCH candidates based on a search space equation.The search space equation may determine the EPDCCH candidates based onthe ECCE indexes included in the EPDCCH candidates. In some embodiments,the same search space equation may be used to determine the localizedEPDCCH candidates and the distributed EPDCCH candidates. As discussedabove, the same set of ECCE indexes for both localized and distributedEPDCCH candidates may provide localized EPDCCH candidates spread amongthe PRB-pairs of the EPDCCH-PRB set, and may provide distributed EPDCCHcandidates spread among the localized ECCEs of the EPDCCH-PRB set.

In one example, the a set of ECCEs corresponding to an EPDCCH candidatem of the set of distributed EPDCCH candidates, as given by the searchspace equation:

${{L\left\{ {\left( {Y_{p,k} + \left\lfloor \frac{m \cdot N_{{ECCE},\; p,\; k}}{L \cdot M_{p}^{(L)}} \right\rfloor + b} \right){mod}\;\left\lfloor {N_{{ECCE},\; p,\; k}/L} \right\rfloor} \right\}} + i};$where p is an identifier of the set of EPDCCH candidates; Y_(p,k) is astarting candidate index for the set of EPDCCH candidates; L is anaggregation level of an EPDCCH to be transmitted on one of the EPDCCHcandidates; M_(p) ^((L)) is a number of EPDCCH candidates in the set ofEPDCCH candidates; k is a subframe associated with the UE; N_(ECCE,p,k)is a total number of CCEs in a control region of subframe k in thewireless communication network; i=0, . . . , L−1; m=0, 1, . . . , M_(p)^((L))−1; and b is equal to a carrier indicator field value for aserving cell associated with the set of EPDCCH candidates or 0 (e.g., ifno carrier indicator field is configured for the UE).

In various embodiments, the set of EPDCCH candidates may be determinedbased on a starting candidate index (e.g., Y_(k)). As discussed above,in some embodiments a plurality of sets of EPDCCH candidates may bedetermined for the UE 108. In some embodiments, different startingcandidate indexes may be used to determine the different sets of EPDCCHcandidates. That is, the starting candidate index may be specific to theEPDCCH candidate. For example, in some embodiments, the startingcandidate indexes for different sets of EPDCCH candidates may beindependently determined using different random numbers. In otherembodiments, the starting candidate indexes may be separated by apre-defined offset. Using different starting candidate indexes todetermine different sets of EPDCCH candidates for the same UE (e.g., UE108) may provide separation in the frequency domain between thedifferent sets of EPDCCH candidates. This may provide flexibility forthe eNB 104 in choosing between the sets of EPDCCH candidates.

Additionally, or alternatively, in some embodiments, for a UE (e.g., UE108) that is configured with multiple EPDCCH-PRB sets, the number ofEPDCCH candidates for the individual EPDCCH-PRB sets may be proportionalto a number of PRB-pairs in the EPDCCH-PRB set. For example, the eNB 104may configure first and second EPDCCH-PRB sets for the UE 108. The firstEPDCCH-PRB set may include a first number of PRB-pairs, and the secondEPDCCH-PRB set may include a second number of PRB-pairs. In variousembodiments, a ratio of a number of EPDCCH candidates in the first setof EPDCCH candidates to a number of EPDCCH candidates in the second setof EPDCCH candidates may be about equal to a ratio of the first numberof PRB-pairs to the second number of PRB-pairs. By “about equal,” it ismeant that the ratios may be equal or may differ slightly because ofrounding to whole numbers of PRB-pairs and/or EPDCCH candidates. Theratio of number of EPDCCH candidates in the first set of EPDCCHcandidates compared with the number of EPDCCH candidates in the secondset of EPDCCH candidates may be measured with a same aggregation level.

In one example, the first EPDCCH-PRB set may include eight PRB-pairs andthe second EPDCCH-PRB set may include four PRB-pairs. Accordingly, thefirst set of EPDCCH candidates for the first EPDCCH-PRB set may includetwice as many EPDCCH candidates as the second set of EPDCCH candidatesfor the second EPDCCH-PRB set. For example, if 18 total EPDCCHcandidates are to be determined, the first set of EPDCCH candidates mayinclude 12 EPDCCH candidates and the second set of EPDCCH candidates mayinclude 6 EPDCCH candidates.

Accordingly, the number of EPDCCH candidates for each EPDCCH-PRB set maybe determined based on the number of PRB-pairs in the EPDCCH-PRB set.This may help balance the loading of the PRB-pairs between the multipleEPDCCH-PRB sets.

FIG. 5 illustrates a method 500 that may be performed by an eNB (e.g.,eNB 104) in accordance with various embodiments. In some embodiments,the eNB may include and/or have access to one or more computer-readablemedia having instructions stored thereon, that, when executed, cause theeNB to perform the method 500.

At 504 the method 500 may include configuring, for a UE (e.g., UE 108),an EPDCCH-PRB set (e.g., EPDCCH-PRB set 200) including a plurality ofPRB pairs. The plurality of PRB-pairs may include a plurality of EREGsarranged into a plurality of localized ECCEs having EREGs of a samePRB-pair and a plurality of distributed ECCEs having EREGs distributedamong the plurality of PRB-pairs.

At 508, the method 500 may further include determining a set ofdistributed EPDCCH candidates for the UE from the EPDCCH-PRB set. Theindividual distributed EPDCCH candidates may include one or more of thedistributed ECCEs. The different distributed EPDCCH candidates may bespread among different localized ECCEs of the PRB-pairs, as describedherein. In some embodiments, the set of distributed EPDCCH candidatesmay include at least one EREG from each of the plurality of localizedECCEs.

In some embodiments, the method 500 may further include determining aset of localized EPDCCH candidates for the UE or another UE. In someembodiments, the set of distributed EPDCCH candidates and the set oflocalized EPDCCH candidates may be determined based on the same searchspace equation. In some embodiments, the set of localized EPDCCHcandidates may include localized ECCEs of each of the plurality ofPRB-pairs of the EPDCCH-PRB set. In some embodiments, the set oflocalized EPDCCH candidates and the set of distributed EPDCCH candidatesmay be determined using different starting candidate indexes.

At 512, the method 500 may further include transmitting an EPDCCHincluding DCI for the UE on one of the EPDCCH candidates.

FIG. 6 illustrates a method 600 that may be performed by a UE (e.g., UE108) in accordance with various embodiments. In some embodiments, the UEmay include and/or have access to one or more computer-readable mediahaving instructions stored thereon, that, when executed, cause the UE toperform the method 600.

At 604, the method 600 may include receiving configuration parametersfrom an eNB (e.g., eNB 104) for an EPDCCH-PRB set. The EPDCCH-PRB setmay include a plurality of PRB-pairs, and the PRB-pars may include aplurality of distributed ECCEs having EREGs of more than one of thePRB-pairs.

At 608, the method 600 may include receiving a set of distributed EPDCCHcandidates from the eNB. The individual distributed EPDCCH candidatesmay include one or more of the distributed ECCEs of the EPDCCH-PRB set.The different distributed EPDCCH candidates may be spread amongdifferent localized ECCEs of the PRB-pairs, as described herein. In someembodiments, the set of distributed EPDCCH candidates may include atleast one EREG from each of a plurality of localized ECCEs of thePRB-pairs.

At 612, the method 600 may include decoding EPDCCHs received by the UEon the distributed EPDCCH candidates to identify the EPDCCH designatedfor the UE.

In some embodiments, the UE may further receive configuration parametersfor another EPDCCH-PRB set. The UE may also receive another set ofEPDCCH candidates corresponding to groups of one or more distributed orlocalized ECCEs of the other EPDCCH-PRB set. In some embodiments, thesecond EPDCCH-PRB set may at least partially overlap with the firstEPDCCH-PRB set (e.g., may include one or more of the same PRB-pairs).

The eNB 104 and/or UE 108 described herein may be implemented into asystem using any suitable hardware and/or software to configure asdesired. FIG. 7 illustrates, for one embodiment, an example system 700comprising one or more processor(s) 704, system control logic 708coupled with at least one of the processor(s) 704, system memory 712coupled with system control logic 708, non-volatile memory (NVM)/storage716 coupled with system control logic 708, a network interface 720coupled with system control logic 708, and input/output (I/O) devices732 coupled with system control logic 708.

The processor(s) 704 may include one or more single-core or multi-coreprocessors. The processor(s) 704 may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, baseband processors, etc.).

System control logic 708 for one embodiment may include any suitableinterface controllers to provide for any suitable interface to at leastone of the processor(s) 704 and/or to any suitable device or componentin communication with system control logic 708.

System control logic 708 for one embodiment may include one or morememory controller(s) to provide an interface to system memory 712.System memory 712 may be used to load and store data and/orinstructions, for example, for system 700. System memory 712 for oneembodiment may include any suitable volatile memory, such as suitabledynamic random access memory (DRAM), for example.

NVM/storage 716 may include one or more tangible, non-transitorycomputer-readable media used to store data and/or instructions, forexample. NVM/storage 716 may include any suitable non-volatile memory,such as flash memory, for example, and/or may include any suitablenon-volatile storage device(s), such as one or more hard disk drive(s)(HDD(s)), one or more compact disk (CD) drive(s), and/or one or moredigital versatile disk (DVD) drive(s), for example.

The NVM/storage 716 may include a storage resource physically part of adevice on which the system 700 is installed or it may be accessible by,but not necessarily a part of, the device. For example, the NVM/storage716 may be accessed over a network via the network interface 720 and/orover Input/Output (I/O) devices 732.

Network interface 720 may have a transceiver 722 to provide a radiointerface for system 700 to communicate over one or more network(s)and/or with any other suitable device. The transceiver 722 may implementcommunications module 120 of UE 108 or communications module 132 of eNB104. In various embodiments, the transceiver 722 may be integrated withother components of system 700. For example, the transceiver 722 mayinclude a processor of the processor(s) 704, memory of the system memory712, and NVM/Storage of NVM/Storage 716. Network interface 720 mayinclude any suitable hardware and/or firmware. Network interface 720 mayinclude a plurality of antennas to provide a multiple input, multipleoutput radio interface. Network interface 720 for one embodiment mayinclude, for example, a wired network adapter, a wireless networkadapter, a telephone modem, and/or a wireless modem.

For one embodiment, at least one of the processor(s) 704 may be packagedtogether with logic for one or more controller(s) of system controllogic 708. For one embodiment, at least one of the processor(s) 704 maybe packaged together with logic for one or more controllers of systemcontrol logic 708 to form a System in Package (SiP). For one embodiment,at least one of the processor(s) 704 may be integrated on the same diewith logic for one or more controller(s) of system control logic 708.For one embodiment, at least one of the processor(s) 704 may beintegrated on the same die with logic for one or more controller(s) ofsystem control logic 708 to form a System on Chip (SoC).

In various embodiments, the I/O devices 732 may include user interfacesdesigned to enable user interaction with the system 700, peripheralcomponent interfaces designed to enable peripheral component interactionwith the system 700, and/or sensors designed to determine environmentalconditions and/or location information related to the system 700.

In various embodiments, the user interfaces could include, but are notlimited to, a display (e.g., a liquid crystal display, a touch screendisplay, etc.), a speaker, a microphone, one or more cameras (e.g., astill camera and/or a video camera), a flashlight (e.g., a lightemitting diode flash), and a keyboard.

In various embodiments, the peripheral component interfaces may include,but are not limited to, a non-volatile memory port, a universal serialbus (USB) port, an audio jack, and a power supply interface.

In various embodiments, the sensors may include, but are not limited to,a gyro sensor, an accelerometer, a proximity sensor, an ambient lightsensor, and a positioning unit. The positioning unit may also be partof, or interact with, the network interface 720 to communicate withcomponents of a positioning network, e.g., a global positioning system(GPS) satellite.

In various embodiments, the system 700 may be a mobile computing devicesuch as, but not limited to, a laptop computing device, a tabletcomputing device, a netbook, a smartphone, etc. In various embodiments,system 700 may have more or less components, and/or differentarchitectures.

EXAMPLES

Various embodiments provide an apparatus including: a communicationsmodule to communicate with a UE over a wireless communication network;and a control module coupled to the communications module. The controlmodule is to: configure, for the UE, an EPDCCH-PRB set including aplurality of PRB-pairs, wherein the EPDCCH-PRB set is configured as adistributed EPDCCH-PRB set having distributed ECCEs that include EREGsspread among the plurality of PRB-pairs; and determine a set ofdistributed EPDCCH candidates for the UE from the PRB-pairs of theEPDCCH-PRB set, wherein the individual distributed EPDCCH candidatesinclude one or more of the distributed ECCEs, and wherein the differentdistributed EPDCCH candidates of the set of distributed EPDCCHcandidates are first mapped to distributed ECCEs including EREGs ofdifferent localized ECCEs of the PRB-pairs, and then mapped todistributed ECCEs including EREGs of a same localized ECCE as anotherdistributed EPDCCH candidate.

In some embodiments, the EPDCCH-PRB set is a first EPDCCH-PRB set,wherein the control module is to determine the set of distributed EPDCCHcandidates based on a search space equation, and wherein the controlmodule is further to: configure, for the UE or another UE, a secondEPDCCH-PRB set including a plurality of PRB-pairs that are fullyoverlapped, partially overlapped, or fully non-overlapped with thePRB-pairs of the first EPDCCH-PRB set, wherein the second EPDCCH-PRB setis configured as a localized EPDCCH-PRB set including a plurality oflocalized ECCEs having EREGs of a same PRB-pair; and determine, based onthe search space equation, a set of localized EPDCCH candidates for theUE or the another UE from the second EPDCCH-PRB set. In some suchembodiments, the set of localized EPDCCH candidates includes localizedECCEs of each of the plurality of PRB-pairs of the second EPDCCH-PRBset.

In some embodiments, the EPDCCH-PRB set includes four PRB-pairs andsixteen distributed ECCEs, and wherein the individual PRB-pairs includefour localized ECCEs.

In some embodiments, the set of distributed EPDCCH candidates is a firstset of EPDCCH candidates, wherein the control module is furtherconfigured to determine a second set of EPDCCH candidates for the UE,and wherein the control module is configured to determine the first andsecond sets of EPDCCH candidates based on respective first and secondstarting candidate indexes that are different from one another. In somesuch embodiments, the first and second starting candidate indexes areseparated by a pre-defined offset.

In some embodiments, the control module is further configured totransmit an EPDCCH including DCI for the UE on one of the distributedEPDCCH candidates.

In some embodiments, a set of ECCEs corresponding to an EPDCCH candidatem of the set of distributed EPDCCH candidates is given by

${{L\left\{ {\left( {Y_{p,k} + \left\lfloor \frac{m \cdot N_{{ECCE},\; p,\; k}}{L \cdot M_{p}^{(L)}} \right\rfloor + b} \right){mod}\;\left\lfloor {N_{{ECCE},\; p,\; k}/L} \right\rfloor} \right\}} + i};$where p is an identifier of the set of distributed EPDCCH candidates;Y_(p,k) is a starting candidate index for the set of distributed EPDCCHcandidates; L is an aggregation level of an EPDCCH to be transmitted onone of the distributed EPDCCH candidates; M_(p) ^((L)) is a number ofEPDCCH candidates in the set of distributed EPDCCH candidates; k is asubframe associated with the UE; N_(ECCE,p,k) is a total number of CCEsin a control region of subframe k in the wireless communication network;i=0, . . . , L−1; m=0, 1, . . . , M_(p) ^((L))−1; and b is equal to acarrier indicator field value for a serving cell associated with the setof distributed EPDCCH candidates or 0.

Some embodiments provide that the EPDCCH-PRB set is a first EPDCCH-PRBset having a first number of PRB-pairs, and that the control module isfurther to: configure the UE with a second EPDCCH-PRB set having asecond number of PRB-pairs; wherein the second EPDCCH-PRB set is adistributed EPDCCH-PRB set or a localized EPDCCH-PRB set; and wherein anumber of EPDCCH candidates in the set of distributed EPDCCH candidatesof the first EPDCCH-PRB set is based on a proportion of the first numberof PRB-pairs relative to the second number of PRB-pairs.

Some embodiments provide an eNB comprising the apparatus as describedabove, and further comprising an Ethernet connection.

In various embodiments, an apparatus to be employed by an eNB tofacilitate transmission of a control channel includes: a communicationsmodule to communicate with a UE over a wireless communication network;and a control module coupled to the communications module. The controlmodule is to: configure, for one or more UEs, a localized EPDCCH-PRB sethaving a plurality of localized ECCEs, and a distributed EPDCCH-PRB sethaving a plurality of distributed ECCEs; and determine, based on asearch space equation, a set of localized EPDCCH candidates, wherein theindividual localized EPDCCH candidates correspond to one or morelocalized ECCEs of the localized EPDCCH-PRB set; and determine, based onthe search space equation, a set of distributed EPDCCH candidates,wherein the individual distributed EPDCCH candidates correspond to oneor more of the distributed ECCEs of the distributed EPDCCH-PRB set.

In some embodiments, the set of localized EPDCCH candidates includesECCEs of each of the plurality of PRB-pairs of the localized EPDCCH-PRBset.

In some embodiments, the different distributed EPDCCH candidates of theset of distributed EPDCCH candidates are first mapped to distributedECCEs including EREGs of different localized ECCEs of the PRB-pairs, andthen mapped to distributed ECCEs including EREGs of a same localizedECCE as another distributed EPDCCH candidate.

In some embodiments, the localized ECCEs are associated with a first setof PRB-pairs, wherein the distributed ECCEs are associated with a secondset of PRB-pairs, and wherein the first and second sets of PRB-pairsinclude one or more common PRB-pairs.

In some embodiments, the distributed EPDCCH candidates have anaggregation level indicating a number of distributed ECCEs included inthe individual distributed EPDCCH candidates, wherein the distributedEPDCCH candidates have an aggregation level of 2 or greater, and whereinthe individual distributed EPDCCH candidates are first mapped todistributed EREGs from a same set of localized ECCEs of the PRB-pairs,and then mapped to distributed EREGs from a different set of localizedECCEs if no EREGs in the same set of localized ECCEs are available.

In some embodiments, the search space equation determines the EPDCCHcandidates based on indexes associated with the corresponding ECCEs,wherein the indexes of the localized ECCEs of the localized EPDCCH-PRBset are continuous, and wherein the indexes of the distributed ECCEs ofthe distributed EPDCCH-PRB set are continuous.

In some embodiments, the EPDCCH-PRB set includes four PRB-pairs, andwherein the individual PRB-pairs include four ECCEs.

In various embodiments, an apparatus to be employed by a UE tofacilitate receiving control information includes: a communicationsmodule configured to communicate with an eNB over a wirelesscommunication network; and a decoding module configured to decode anEPDCCH received at one or more of a plurality of EPDCCH candidates of afirst set of EPDCCH candidates and a second set of EPDCCH candidates;wherein the first set of EPDCCH candidates is determined based on afirst starting candidate index and the second set of EPDCCH candidatesis determined based on a second starting candidate index that isdifferent from the first starting candidate index.

In some embodiments, the first and second starting candidate indexes areseparated by a pre-defined offset.

In some embodiments, the first and second starting candidate indexes areindependently determined using different random numbers.

In some embodiments, the EPDCCH candidates of the first and second setscorrespond to one or more ECCEs of respective first or second EPDCCH-PRBsets.

In some embodiments, the first EPDCCH-PRB set is a localized EPDCCH-PRBset including a plurality of localized ECCEs having EREGs of a samePRB-pair, and the second EPDCCH-PRB set is a distributed EPDCCH-PRB setincluding a plurality of distributed ECCEs having EREGs from a pluralityof PRB-pairs.

Various embodiments provide one or more non-transitory computer-readablemedia having instructions, stored thereon, that when executed enable aUE to: receive configuration parameters from an eNB for a firstEPDCCH-PRB set including a first number of PRB-pairs; receiveconfiguration parameters from the eNB for a second EPDCCH-PRB setincluding a second number of PRB-pairs; receive a first set of EPDCCHcandidates from the eNB, wherein the individual EPDCCH candidatescorrespond to one or more ECCEs of the first EPDCCH-PRB set which the UEis to monitor for an EPDCCH; and receive a second set of EPDCCHcandidates from the eNB, wherein the individual EPDCCH candidates of thesecond set of EPDCCH candidates correspond to one or more ECCEs of thesecond EPDCCH-PRB set which the UE is to monitor for an EPDCCH; whereina ratio of a number of EPDCCH candidates in the first set of EPDCCHcandidates to a number of EPDCCH candidates in the second set of EPDCCHcandidates is about equal to a ratio of the first number of PRB-pairs tothe second number of PRB-pairs.

In some embodiments, the first and second EPDCCH-PRB sets are bothconfigured as distributed EPDCCH-PRB sets having distributed ECCEs orboth configured as localized EPDCCH-PRB sets having localized ECCEs.

In some embodiments, the first EPDCCH-PRB set is configured as alocalized EPDCCH-PRB set having localized ECCEs and the secondEPDCCH-PRB set is configured as a distributed EPDCCH-PRB set havingdistributed ECCEs.

In some embodiments, the first number of PRB-pairs is eight, the secondnumber of PRB-pairs is four, and wherein the number of EPDCCH candidatesin the first set of EPDCCH candidates is twice the number of EPDCCHcandidates in the second set of EPDCCH candidates.

In various embodiments, an apparatus to be employed by an eNB tofacilitate transmission of a control channel to a UE includes: means toconfigure, for the UE, an EPDCCH-PRB set including a plurality ofPRB-pairs, wherein the EPDCCH-PRB set is configured as a distributedEPDCCH-PRB set having distributed ECCEs that include EREGs spread amongthe plurality of PRB-pairs; and means to determine a set of distributedEPDCCH candidates for the UE from the PRB-pairs of the EPDCCH-PRB set,wherein the individual distributed EPDCCH candidates include one or moreof the distributed ECCEs, and wherein the different distributed EPDCCHcandidates of the set of distributed EPDCCH candidates are first mappedto distributed ECCEs including EREGs of different localized ECCEs of thePRB-pairs, and then mapped to distributed ECCEs including EREGs of asame localized ECCE as another distributed EPDCCH candidate.

In some embodiments, the EPDCCH-PRB set is a first EPDCCH-PRB set, theset of distributed EPDCCH candidates is determined based on a searchspace equation, and the apparatus further includes: means to configure,for the UE or another UE, a second EPDCCH-PRB set including a pluralityof PRB-pairs that are fully overlapped, partially overlapped, or fullynon-overlapped with the PRB-pairs of the first EPDCCH-PRB set, whereinthe second EPDCCH-PRB set is configured as a localized EPDCCH-PRB setincluding a plurality of localized ECCEs having EREGs of a samePRB-pair; and means to determine, based on the search space equation, aset of localized EPDCCH candidates for the UE or the another UE from thesecond EPDCCH-PRB set.

In some embodiments, the set of localized EPDCCH candidates includeslocalized ECCEs of each of the plurality of PRB-pairs of the secondEPDCCH-PRB set.

In some embodiments, the EPDCCH-PRB set includes four PRB-pairs andsixteen distributed ECCEs, and the individual PRB-pairs include fourlocalized ECCEs

In various embodiments, an apparatus to be employed by an eNB tofacilitate transmission of control information: one or morecomputer-readable storage media configured to store a plurality ofinstructions; and one or more processors coupled to the one or morecomputer-readable storage media, the one or more processors, in responseto executing the plurality of instructions, being configured to:configure, for one or more UEs, a localized EPDCCH-PRB set having aplurality of localized ECCEs, and a distributed EPDCCH-PRB set having aplurality of distributed ECCEs; and determine, based on a search spaceequation, a set of localized EPDCCH candidates, wherein the individuallocalized EPDCCH candidates correspond to one or more localized ECCEs ofthe localized EPDCCH-PRB set; and determine, based on the search spaceequation, a set of distributed EPDCCH candidates, wherein the individualdistributed EPDCCH candidates correspond to one or more of thedistributed ECCEs of the distributed EPDCCH-PRB set.

In some embodiments, the set of localized EPDCCH candidates includesECCEs of each of the plurality of PRB-pairs of the localized EPDCCH-PRBset.

In some embodiments, the different distributed EPDCCH candidates of theset of distributed EPDCCH candidates are first mapped to distributedECCEs including EREGs of different localized ECCEs of the PRB-pairs, andthen mapped to distributed ECCEs including EREGs of a same localizedECCE as another distributed EPDCCH candidate.

In some embodiments, the localized ECCEs are associated with a first setof PRB-pairs, wherein the distributed ECCEs are associated with a secondset of PRB-pairs, and wherein the first and second sets of PRB-pairsinclude one or more common PRB-pairs.

In some embodiments, the distributed EPDCCH candidates have anaggregation level indicating a number of distributed ECCEs included inthe individual distributed EPDCCH candidates, wherein the distributedEPDCCH candidates have an aggregation level of 2 or greater, and whereinthe individual distributed EPDCCH candidates are first mapped todistributed EREGs from a same set of localized ECCEs of the PRB-pairs,and then mapped to distributed EREGs from a different set of localizedECCEs if no EREGs in the same set of localized ECCEs are available.

Various embodiments provide an apparatus to be employed by an eNB tofacilitate transmission of a control channel, the apparatus including:means for configuring, for a user equipment (UE), a first enhancedphysical downlink control channel (EPDCCH) physical resource block (PRB)set including a plurality of enhanced control channel elements (ECCEs);means for configuring, for the UE, a second EPDCCH-PRB set including aplurality of ECCEs; means for determining, based on a first startingcandidate index, a first set of EPDCCH candidates corresponding to oneor more ECCEs of the first EPDCCH-PRB set; and means for determining,based on a second starting candidate index that is different from thefirst starting candidate index, a second set of EPDCCH candidatescorresponding to one or more ECCEs of the second EPDCCH-PRB set.

In some embodiments, the first and second starting candidate indexes areseparated by a pre-defined offset.

In some embodiments, the first and second starting candidate indexes areindependently determined using different random numbers.

In some embodiments, the first set of EPDCCH candidates includeslocalized EPDCCH candidates corresponding to one or more localized ECCEshaving EREGs of a same PRB-pair, and wherein the second set of EPDCCHcandidates includes distributed EPDCCH corresponding to one or moreECCEs having EREGs from a plurality of PRB-pairs.

In some embodiments, the apparatus further includes means fortransmitting an EPDCCH for the UE on an EPDCCH candidate of the first orsecond set of EPDCCH candidates.

Various embodiments provide an apparatus to be employed by a UE tofacilitate receipt of control information, the apparatus including:means to receive configuration parameters from an eNB for a firstEPDCCH-PRB set including a first number of PRB-pairs; means to receiveconfiguration parameters from the eNB for a second EPDCCH-PRB setincluding a second number of PRB-pairs; means to receive a first set ofEPDCCH candidates from the eNB, wherein the individual EPDCCH candidatescorrespond to one or more enhanced control channel elements (ECCEs) ofthe first EPDCCH-PRB set which the UE is to monitor for an EPDCCH; andmeans to receive a second set of EPDCCH candidates from the eNB, whereinthe individual EPDCCH candidates of the second set of EPDCCH candidatescorrespond to one or more ECCEs of the second EPDCCH-PRB set which theUE is to monitor for an EPDCCH; wherein a ratio of a number of EPDCCHcandidates in the first set of EPDCCH candidates to a number of EPDCCHcandidates in the second set of EPDCCH candidates is about equal to aratio of the first number of PRB-pairs to the second number ofPRB-pairs.

In some embodiments, the first and second EPDCCH-PRB sets are bothconfigured as distributed EPDCCH-PRB sets having distributed ECCEs orboth configured as localized EPDCCH-PRB sets having localized ECCEs.

In some embodiments, the first EPDCCH-PRB set is configured as alocalized EPDCCH-PRB set having localized ECCEs and the secondEPDCCH-PRB set is configured as a distributed EPDCCH-PRB set havingdistributed ECCEs.

In some embodiments, the first number of PRB-pairs is eight, the secondnumber of PRB-pairs is four, and wherein the number of EPDCCH candidatesin the first set of EPDCCH candidates is twice the number of EPDCCHcandidates in the second set of EPDCCH candidates.

Although certain embodiments have been illustrated and described hereinfor purposes of description, a wide variety of alternate and/orequivalent embodiments or implementations calculated to achieve the samepurposes may be substituted for the embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatembodiments described herein be limited only by the claims and theequivalents thereof.

What is claimed is:
 1. One or more non-transitory computer-readablemedia having instructions, stored thereon, that when executed cause anevolved Node B (eNB) to: configure, for a user equipment (UE) of awireless communication network, a distributed enhanced physical downlinkcontrol channel (EPDCCH)-physical resource block (PRB) set; determine aset of distributed EPDCCH candidates for the UE from the distributedEPDCCH-PRB set, wherein a set of distributed enhanced control channelelements (ECCEs) corresponding to an EPDCCH candidate m of the set ofdistributed EPDCCH candidates is given by${{L\left\{ {\left( {Y_{p,k} + \left\lfloor \frac{m \cdot N_{{ECCE},\; p,\; k}}{L \cdot M_{p}^{(L)}} \right\rfloor + b} \right){mod}\;\left\lfloor {N_{{ECCE},\; p,\; k}/L} \right\rfloor} \right\}} + i};$where p is an identifier of the set of distributed EPDCCH candidates;Y_(p,k) is a starting candidate index for the set of distributed EPDCCHcandidates; L is an aggregation level of an EPDCCH to be transmitted onone of the distributed EPDCCH candidates; M_(p) ^((L)) is a number ofEPDCCH candidates in the set of distributed EPDCCH candidates; k is asubframe associated with the UE; N_(ECCE,p,k) is a total number of ECCEsin a control region of subframe k in the wireless communication network;i=0, . . . , L−1; m=0, 1, . . . , M_(p) ^((L))−1; and b is equal to acarrier indicator field value for a serving cell associated with the setof distributed EPDCCH candidates or 0; and transmit an EPDCCH to the UEon one or more of the distributed EPDCCH candidates.
 2. The one or moremedia of claim 1, wherein the distributed EPDCCH-PRB set includes aplurality of PRB-pairs, and wherein distributed ECCEs of the distributedEPDCCH-PRB set include enhanced resource element groups (EREGs) spreadamong the plurality of PRB-pairs.
 3. The one or more media of claim 1,wherein the distributed EPDCCH-PRB set includes four PRB-pairs andsixteen distributed ECCEs, and wherein the individual PRB-pairs includefour localized ECCEs.
 4. The one or more media of claim 1, wherein theset of distributed EPDCCH candidates is a first set of EPDCCHcandidates, wherein the instructions, when executed, further cause theeNB to determine a second set of EPDCCH candidates for the UE, andwherein the first and second sets of EPDCCH candidates are determinedbased on respective first and second starting candidate indexes that aredifferent from one another.
 5. The one or more media of claim 1, whereinthe instructions, when executed, further cause the eNB to: configure,for the UE or another UE, a localized EPDCCH-PRB set including aplurality of localized ECCEs, individual localized ECCEs having EREGs ofa same PRB-pair; determine a set of localized EPDCCH candidates for theUE or the another UE from the localized EPDCCH-PRB set, wherein thelocalized EPDCCH candidates are determined according to${{L\left\{ {\left( {Y_{p,k} + \left\lfloor \frac{m \cdot N_{{ECCE},\; p,\; k}}{L \cdot M_{p}^{(L)}} \right\rfloor + b} \right){mod}\;\left\lfloor {N_{{ECCE},\; p,\; k}/L} \right\rfloor} \right\}} + i};$ and transmit another EPDCCH to the UE or the another UE on one or moreof the localized EPDCCH candidates.
 6. The one or more media of claim 1,wherein the instructions, when executed, further cause the eNB to:configure, for the UE or another UE, a localized EPDCCH-PRB setincluding a plurality of localized ECCEs, wherein individual localizedECCEs have EREGs of a same PRB-pair, and wherein the localizedEPDCCH-PRB set includes one or more common resources with thedistributed EPDCCH-PRB set; determine a set of localized EPDCCHcandidates for the UE or the another UE from the localized EPDCCH-PRBset; and transmit another EPDCCH to the UE or the another UE on one ormore of the localized EPDCCH candidates.
 7. The one or more media ofclaim 4, wherein the first and second starting candidate indexes areseparated by a pre-defined offset.
 8. One or more non-transitorycomputer-readable media having instructions, stored thereon, that whenexecuted by one or more processors of a user equipment (UE) in awireless communication network, cause the UE to: determine a set ofdistributed enhanced physical downlink control channel (EPDCCH)candidates from a distributed EPDCCH-physical resource block (PRB) set,wherein a set of distributed enhanced control channel elements (ECCEs)corresponding to an EPDCCH candidate m of the set of distributed EPDCCHcandidates is given by${{L\left\{ {\left( {Y_{p,k} + \left\lfloor \frac{m \cdot N_{{ECCE},\; p,\; k}}{L \cdot M_{p}^{(L)}} \right\rfloor + b} \right){mod}\;\left\lfloor {N_{{ECCE},\; p,\; k}/L} \right\rfloor} \right\}} + i};$where p is an identifier of the set of distributed EPDCCH candidates;Y_(p,k) is a starting candidate index for the set of distributed EPDCCHcandidates; L is an aggregation level of an EPDCCH to be transmitted onone of the distributed EPDCCH candidates; M_(p) ^((L)) is a number ofEPDCCH candidates in the set of distributed EPDCCH candidates; k is asubframe associated with the UE; N_(ECCE,p,k) is a total number of ECCEsin a control region of subframe kin the wireless communication network;i=0, . . . , L−1; m=0, 1, . . . , M_(p) ^((L))−1; and b is equal to acarrier indicator field value for a serving cell associated with the setof distributed EPDCCH candidates or 0; and monitor the distributedEPDCCH candidates for an EPDCCH including downlink control information(DCI) for the UE.
 9. The one or more media of claim 8, wherein theinstructions, when executed, further cause the UE to obtainconfiguration instructions, via wireless signaling from an evolved NodeB (eNB) of the wireless communication network, for the distributedEPDCCH-PRB set.
 10. The one or more media of claim 8, wherein thedistributed EPDCCH-PRB set includes a plurality of PRB-pairs, andwherein distributed ECCEs of the distributed EPDCCH-PRB set includeenhanced resource element groups (EREGs) spread among the plurality ofPRB-pairs.
 11. The one or more media of claim 8, wherein the distributedEPDCCH-PRB set includes four PRB-pairs and sixteen distributed ECCEs,and wherein the individual PRB-pairs include four localized ECCEs. 12.The one or more media of claim 8, wherein the set of distributed EPDCCHcandidates is a first set of EPDCCH candidates, wherein theinstructions, when executed, further cause the UE to determine a secondset of EPDCCH candidates for the UE, and wherein the first and secondsets of EPDCCH candidates are determined based on respective first andsecond starting candidate indexes that are different from one another.13. The one or more media of claim 8, wherein the instructions, whenexecuted, further cause the UE to: determine a set of localized EPDCCHcandidates from a localized EPDCCH-PRB set including a plurality oflocalized ECCEs, wherein individual localized ECCEs have EREGs of a samePRB-pair, and wherein the localized EPDCCH candidates are determinedaccording to${{L\left\{ {\left( {Y_{p,k} + \left\lfloor \frac{m \cdot N_{{ECCE},\; p,\; k}}{L \cdot M_{p}^{(L)}} \right\rfloor + b} \right){mod}\;\left\lfloor {N_{{ECCE},\; p,\; k}/L} \right\rfloor} \right\}} + i};$ and monitor the localized EPDCCH candidates for another EPDCCHincluding DCI for the UE.
 14. The one or more media of claim 8, whereinthe instructions, when executed, further cause the UE to: determine aset of localized EPDCCH candidates from a localized EPDCCH-PRB setincluding a plurality of localized ECCEs, wherein individual localizedECCEs have EREGs of a same PRB-pair, and wherein the localizedEPDCCH-PRB set includes one or more common resources with thedistributed EPDCCH-PRB set; and monitor the localized EPDCCH candidatesfor another EPDCCH including DCI for the UE.
 15. The one or more mediaof claim 8, wherein the instructions, when executed, further cause theUE to receive the EPDCCH on one or more of the distributed EPDCCHcandidates.
 16. The one or more media of claim 12, wherein the first andsecond starting candidate indexes are separated by a pre-defined offset.17. An evolved Node B (eNB) comprising: one or more processors; a memorycoupled to the one or more processors, the memory having instructions,stored thereon, that when executed by the one or more processors, causethe eNB to: determine a first set of enhanced physical downlink controlchannel (EPDCCH) candidates for a user equipment (UE) using enhancedcontrol channel elements (ECCEs) that are selected from a firstEPDCCH-physical resource block (PRB) set based on a first startingcandidate index; determine a second set of EPDCCH candidates for the UEusing ECCEs that are selected from a second EPDCCH-PRB set based on asecond starting candidate index that is different from the firststarting candidate index; and transmit an EPDCCH to the UE on one ormore EPDCCH candidates of the first set of EPDCCH candidates or thesecond set of EPDCCH candidates.
 18. The eNB of claim 17, wherein thefirst set of EPDCCH candidates and the second set of EPDCCH candidatesinclude resources of a same subframe.
 19. The eNB of claim 17, whereinthe first and second starting candidate indexes are separated by apre-defined offset.
 20. The eNB of claim 17, wherein the first andsecond starting candidate indexes are independently determined usingdifferent random numbers.
 21. The eNB of claim 17, wherein the firstEPDCCH-PRB set is a localized EPDCCH-PRB set including a plurality oflocalized ECCEs having enhanced resource element groups (EREGs) of asame PRB-pair, and the second EPDCCH-PRB set is a distributed EPDCCH-PRBset including a plurality of distributed ECCEs having EREGs from aplurality of PRB-pairs.